The authors agree that the surname was formed from the Germanic personal name Adalger, composed of athala ("nobility") and gaira/gher ("spear"), meaning "noble spear" or "illustrious spear".

V. Blunda, for the Sicilian variant, derives it from the Germanic compound Athala Gaira. He notes that the spear was the distinctive weapon of the free Lombard man, a symbol of his full belonging to the warrior community. He adds that the variant Maugeri, with a phonetic change of the initial consonant, is peculiar to the Sicilian dialect and is documented especially in the eastern area of the island.

It is considered to be a widespread anthroponymic surname, derived from Adalger ("noble spear"). Aldegani, Algani and Algarotti are recorded as similar surnames.